Fuel Pump delete?

[Blue Bomber Man]

I dont have a strong automotive background, but it seems to me that it might be possible to completely remove the fuel pump system, by creating an air tight fuel system (including the gas tank) and pressurizing a the tank with air to push the fuel through the system.

Any reason this would not be possible?

Thoughts on this?

[vtec-e]

Kudos for thinking outside the box!
I'd say safety would be the primary issue here. A pressurised vessel with gasoline in it is a serious piece of kit. Fuel cut off in a crash would have to be fool proof and completely reliable. Testing would have to be extensive.
What would the advantages anyway? You'd need a compressor to pressurise the tank, which would probably use more power than the fuel pump would in the first place.
Also, if your fuel system uses a fuel return to the tank, how are you going to get the unused fuel back in there?
Good luck with the project!

ollie

[almightybmw]

Honestly, this is a bad idea. There's a reason they created the charcoal canister venting to the intake manifold, keeps the fumes pressurized in the engine and it doesn't create that wonderful pop when you pull the gas cap.

The closest you could come to this idea is using a fuel cell with a pressurized air bladder, to keep the fuel over the pump when under high lateral G forces, ie racing applications. But those tanks don't allow for filling up at the pump, you have to have a specialized filler to push against the air bladder without it forcing fuel out.

You could always go back to the days of float bowls on carbs if you really don't want the electrical load. It'd just be vacuum load then.

[Ryland]

my fuel pressure on my civic I believe is around 35psi, or about what alot of car tires are running at, having a gas tank at that pressure would freak me out, dealing with the high pressure side of the fuel system is bad enough when changing filters, opening a gas cap that wanted to strike me in the face with nearly 70 pounds of force (2 square inch opening) you would see lot of people at gas stations with black eyes and broken arms.

[dcb]

This is how RC airplanes work actually, a little pressure tap on the muffler pushes the fuel to the carb. It's only pressurized while the engine is running, and is a pretty damn simple setup. It is low pressure though, and most everything I know of has gone the route of high pressure. That is not to say an accurate low pressure system is impossible or anything.

But if you are thinking of a high pressure system, then you still have to pump something (air instead of fuel) and you would lose out, energy wise, and that whole high pressurize tank thing that would have to be a lot heavier to handle the pressure without distorting, etc.

[bgd73]

A carb can do it. I pulled two pumps from 80s subarus that ran intermittent and nearly siezed...carb only.No problems. my latest was 21 years old and I decided to change it..barely worked for a bench test. that means <1psi to atomize, after bringing it to the engine...and the displacement has to be small on real carb 3 degree cams...and a pressure for cold starts in a burst, as the engine carb timed picks it up very fast. I also used to run alot of v8s with the pump driven off the cams...they all had problems with leaky diaghrams, meaning...not even 5psi to run a v8..and they still ran. Slobs, but ran. There is fuel cell concepts that help keep pressure down for same chore as well. Injection is satan.

Ideas like yours are excellent and never bad opinioned by my own experience of unbelievably miraculously impossible running engines according to a moron like me with 50psi injection and "not enough".It has got to change..love to see questions like this, they can be answered.

[Red]

Originally Posted by bgd73

A carb can do it. I pulled two pumps from 80s subarus that ran intermittent and nearly siezed...carb only.No problems. my latest was 21 years old and I decided to change it..barely worked for a bench test. that means <1psi to atomize, after bringing it to the engine...and the displacement has to be small on real carb 3 degree cams...and a pressure for cold starts in a burst, as the engine carb timed picks it up very fast. I also used to run alot of v8s with the pump driven off the cams...they all had problems with leaky diaghrams, meaning...not even 5psi to run a v8..and they still ran. Slobs, but ran. There is fuel cell concepts that help keep pressure down for same chore as well. Injection is satan.

Ideas like yours are excellent and never bad opinioned by my own experience of unbelievably miraculously impossible running engines according to a gook with 50psi injection and "not enough".It has got to change..love to see questions like this, they can be answered.

For the curious, whats wrong with fuel injection?

[Blue Bomber Man]

So after I posted this I took some time to read up on fuel systems and their quirks, learned that there would be several problems with using an air pressurized fuel system.

1) Vapor lock, the solution that current systems often use is a fuel return line, something that would be very difficult with an air pressurized system.

2) Safety concerns (I think this one could probably be dealt with pretty easily though)

3) Fuel tank integrity, never thought of that until someone posted it up above. This is the main issue that I dont think would make this idea of mine feasible =(

I do think that energy wise the concept would definately be way ahead of fuel pump, but the problems that arise with this system clearly outweigh any modest gains I would get.

Still, Would love to see it done lol

[BlackDeuceCoupe]

Originally Posted by Blue Bomber Man

I dont have a strong automotive background, but it seems to me that it might be possible to completely remove the fuel pump system, by creating an air tight fuel system (including the gas tank) and pressurizing a the tank with air to push the fuel through the system.

Any reason this would not be possible?

Thoughts on this?

Um...

In most fuel injected systems, gasoline travels in a loop - from the gas tank, to the engine, and back to the gas tank again. Round n' round she goes! The injectors use what they need, and the rest goes back to the gas tank, blah, blah, blah.

I don't know ANY way of doing this without a pump...

There are a few closed fuel loop systems out there, but I think they're a distinct minority!

EDIT

Took me a while to Google a pic - but, here's a typical EFI loop...

[BlackDeuceCoupe]

Originally Posted by Blue Bomber Man

1) Vapor lock, the solution that current systems often use is a fuel return line, something that would be very difficult with an air pressurized system.

True that!

It's also the main reason they put the fuel pump INSIDE the gas tank...

I can guarantee that monkeying around with this stuff will mess up your idle too!!!